EDIT1: When you purchase the Humble Indie Bundle, you can use your download code to purchase the entire Penumbra series for $5.

EDIT2: The Humble Indie Bumble has added a new game!

There are a number of indie game developers out there, but since they don't have big names like EA, Sony, Nintendo, Microsoft, Valve, Activison and Ubisoft - and believe me, there are plenty more - they rely on community promotions to make users aware of their developments and to purchase their games.

The latest promotion is the Humble Indie Bundle. Wolfire Games teamed up with two charities (Child's Play Charity, Electronic Frontier Foundation) and four other game developers (2DBoy, Bit Blot, Cryptic Sea, Frictional Games) to release five games for any price you want.

The games include:

• 2DBoy's World of Goo
• Bit Blot's Aquaria
• Cryptic Sea's Gish
• Wolfire Games' Lugaru
• Frictional Games' Penumbra: Overture

World of Goo

An addicting game where you build bridges of goo, from one point to the next, with a little thing called gravity and physics to stop you along the way.

Aquaria

More of a feminine game in style and setup, so I didn't play it much, but the graphics are quite nice (you just have to play the game to see) and my girlfriend seems to like it, so I'm happy.

Gish

A really fun side-scrolling game where you run around as a blob of tar, squeezing through tunnels and sliding along the ground on your way to save your human-friend Brea.

Lugaru

Revenge your family's death as a ravenous bunny out for blood. Features a rag-doll physics engine.

Penumbra: Overture

Yes... the game is that dark. You can adjust the contrast before you start the game.

My favourite game out of the group: A first-person adventure game where you fly to an uninhabited bunker in Greenland and try to dig up clues to your father's past, while evading rabid animals and dark, underground secrets. Quite addicting and quite scary.

When you pay for your games, you can split it evenly between the developers and charity, all to developers, all to charity or any remix you like.

So far the promotion has raised over $500,000 from 64000+ contributions! Not bad.

There is also a battle going on between the three operating systems and who, on average, pays more for their games. At the time of this writing, the stats are: Windows: $7.05, Mac: $9.75, Linux: $13.81.

The great thing about these games is that, once you happily purchase them (I paid $25 CDN) you get a download link for all five games on all three platforms, and the download link never expires just make sure to back them up as the files will only be hosted for a limited time! That means you can play these games on your Windows, Mac and/or Linux installation without the link expiring!

So if you support indie games, or indie developers that release games that are platform neutral (I'm sure a lot of Linux users are thankful), then make sure to donate some cash for five great games! You can pay via Paypal, Visa, Mastercard, American Express, Discover, Amazon.com and Google Checkout.

Happy Gaming!